The problem with "what people think of middle class" is that everyone has a different idea of what it is, depending on where they are on the revenue scale. That leads to discussions like this thread.
Absolutely correct. But we also know that the OCDE definition is a strict percentage which is so absurd it creates large middle classes in cultures which have absolutely no middle class. And events may unfold such that the definition may be absurd even in our own culture in 20? 50? years.